1. Field of the Invention
The present invention relates to a heterogeneous information distribution system such as a video-on-demand (VOD) system. More particularly, the present invention relates to a method and apparatus for processing content and other assets such that each set top terminal (STT) receives at least an asset data stream adapted to the maximal capabilities of the respective STT.
2. Description of the Background Art
Information distribution systems, such as video on demand (VOD) systems providing content encoded according to the various Moving Pictures Experts Group (MPEG) standards are known. For example, a first standard known as MPEG-1 refers to ISO/IEC standards 11172, which is incorporated herein by reference in its entirety. A second standard known as MPEG-2 refers to ISO/IEC standards 13818, which is incorporated herein by reference in its entirety. Additionally, a compressed digital video system is described in the Advanced Television Systems Committee (ATSC) digital television standard document A/53, incorporated herein by reference in its entirety.
An interactive information distribution system provided by DIVA Systems Corporation of Redwood City, Calif. is described in more detail in U.S. Pat. No. 6,253,375, issued Jun. 26, 2001 and incorporated herein by reference in its entirety. Users or subscribers to the DIVA system select information offerings using a “Navigator” functionality, which is described in more detail in U.S. Pat. No. 6,208,335, issued Mar. 27, 2001 and incorporated herein by reference in its entirety. Briefly, the Navigator utilizes a combination of MPEG content (such as MPEG video content and related MPEG audio content) and Navigator asset data to provide viewers with a means of selecting and ordering services. Navigator assets include bitmaps and navigation control scripts. As the set top box user is “navigating,” the set top box extracts the asset data from a transport stream including video content and asset data and uses that data to provide bitmap overlays on top of the MPEG content. The control data within the asset data is used to define the layout of the screen and to take actions based on viewer input.
Unfortunately, within the context of an information distribution system utilizing set top terminals (STTs) or set top boxes (STBs) of differing levels of capability (a heterogeneous system), possibly from different manufacturers, asset data suitable for use by one model (e.g., a high capability) set top terminal will not be usable by another model (e.g., a low capability) set top terminal.
Therefore, it is seen to be desirable to provide a method and apparatus for adapting the delivery of assets and/or content to set top terminals within a heterogeneous information distribution system such that a maximal level of capability for each STT is utilized. Moreover, it is seen to be desirable to adapt the delivered assets in a manner tending to avoid additional processing by the STT, such as decoding multiple layers of asset data to retrieve an appropriate layer.